Palynological evidence for organic petroleum origin theory

Abstract

The organic petroleum origin theory considers that petroleum is derived from organic materials produced by biological remains in sediments through thermal transformation. Dispersed insoluble organic matter in sedimentary rock is often called “kerogen,” which is considered as the forerunner of petroleum. Because of the similarity of certain molecular formulas, it is inferred that some kerogen is transformed from sporopollenin. The inorganic petroleum origin theory considers that petroleum originates as a simple hydrocarbon that was dispersed from universal celestial bodies, or it is composed of carbon and hydrogen from magma derived from the depths of the Earth. The discovery of fossil spores and pollen in crude oil from the Beisantai igneous rock petroleum pool in the Junggar Basin provided reliable evidence for the organic petroleum origin theory. It is impossible that igneous rocks would contain uncarbonized biological fossils. The fossil spores and pollen in the crude oils must have been carried by oil, gas, and water from sedimentary source rocks to the igneous reservoir during petroleum migration. The Beisantai crude oil is rich in chemical biomarkers, including beta-carotene, gamma-carotene, cholestane, ergostane, sitostane, hopanes, and terpanes. Such biomarkers have no sources other than the breakdown of organisms, which confirms a biogenic hydrocarbon source.